WASHINGTON (CNN) -- Both Republican and Democratic lawmakers Monday urged President Bush to nominate a replacement for Attorney General Alberto Gonzales who can restore confidence in the Justice Department.

Alberto Gonzales was dogged by controversial issues, including wiretapping programs and fired U.S. attorneys.

Members of both parties were critical of Gonzales' tenure Monday, leaving only a few voices defending him.

"Our country needs a credible, effective attorney general who can work with Congress on critical issues ranging from immigration to investigating terrorism at home and abroad," said Sen. John Sununu, a Republican from New Hampshire.

Noting that he called for the attorney general to leave his post in March, Sununu added, "Alberto Gonzales' resignation will finally allow a new attorney general to take on this task."

Republican Sen. Susan Collins of Maine called the resignation "a positive step forward for the Department of Justice."

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Maine's other Republican, Sen. Olympia Snowe, said the resignation "comes well after the American people had lost confidence in his ability to continue serving in his capacity as head of the Justice Department."

Gonzales came under heavy criticism for a range of issues, including the allegedly politically motivated firings of several U.S. attorneys and a controversial government no-warrant wiretapping program.

Earlier this summer, Gonzales was accused of removing the prosecutors in part because of partisan concerns that they were either not doing enough to prosecute Democrats on voter fraud charges or going too far in pressing corruption charges against Republicans.

In July, in a prepared statement, Gonzales responded: "I believe very strongly that there is no place for political considerations in the hiring of our career employees or in the administration of justice."

On Monday, Bud Cummins, former U.S. attorney for the Eastern District of Arkansas who was one of the attorneys asked to resign, said Gonzales "threw some of my colleagues under the bus."

"It's fairly clear (my colleagues) were selected to be removed because they rankled the local political organization. And the attorney general failed to insulate them," said Cummins.

Both Democratic and Republican critics have said Gonzales also gave misleading testimony to Congress about a controversial wiretapping program.

Some have said the no-warrant wiretap program, which monitored communications into and out of the United States by people with suspected links to al Qaeda, violated the Foreign Intelligence Surveillance Act.

FISA governs electronic surveillance in intelligence cases and generally requires officials to apply to a secret court for a warrant before eavesdropping on U.S. citizens.

White House hopeful John Edwards issued a one-line statement: "Better late than never."

"The president must nominate an attorney general who is a lawyer for the American people not a political arm of the White House," New Mexico Gov. Bill Richardson said in a statement.

Illinois Sen. Barack Obama and presidential candidate said: "I have long believed that Alberto Gonzales subverted justice to promote a political agenda, and so I am pleased that he has finally resigned today. The president needs to nominate an attorney general who will be the people's lawyer, not the president's lawyer."

During a presidential campaign appearance in Cedar Rapids, Iowa, Sen. Hillary Clinton, D-New York, said the next attorney general should "care about the rule of law more than he cares about protecting the president."

Sen. John Cornyn, a Texas Republican, said Gonzales was a victim of a bitter political atmosphere in Washington.

"I think it's a sad day and sad commentary on the hyperpartisan atmosphere in Washington, D.C. He has resigned for basically unproven charges. This is not a high water mark for the Congress," Cornyn said.

Senate Republican Leader Mitch McConnell of Kentucky said the resignation was the result of "poisonous partisanship that we've sadly grown accustomed to over the past eight months."E-mail to a friend